The objectives of this research project are to study the cariostatic effects of amino acids on in vitro plaque formation and cell wall biosynthesis, and to characterize the cell wall structure involved in the bacterial adhesive interaction and the attachment of glucosyltransferase in the cariogenic oral Streptococcus mutans. The research work will employ more refined assay methods for studying in vitro plaque formation in order to correlate this effect with the induction of sugar nucleotide accumulation, and peptidoglycan secretion resulting from amino acid treatment. The accumulated sugar nucleotide and peptidoglycan will be characterized to provide information for the cell wall structure affected by this treatment. Amino acid incorporation into cell wall and their cross-linking in the cell wall will also be studied along with other cell wall structural changes induced by amino acid treatment. N-acetylhexosamines and phytohemagglutinins will be used as specific blocking agents for the characterization of the cell wall receptor structure involved in the binding of glucosyltransferase. Studies will also be conducted to differentiate the dextran and glucosyltransferase binding sites and to examine the distribution of this enzyme under various treatments. Isotope-labeling techniques and various other new methodologies are also to be applied to achieve the specific goals proposed in this research project. S. mutans strain C67-1 and its non-cariogenic mutant strain C67-25 are also to be used for critical study of the various aspects proposed above.